Grit fed blast wheels having a plurality of radially disposed vanes for centrifugally propelling abrasive material grit against parts whereby cleaning same are known in the art. Such wheels generally propel abrasive grit having an RC hardness ranging from 54 to 62. The useful life of such wheels may extend between 5,000 and 10,000 hours depending on the type of grit and the rebound from the objects being blasted.
Although the plate members comprising the wheel assembly are case hardened, a problem exists in industry because of the short useful life of such wheel assemblies. It has been found that the discs of the wheel assembly usually start to wear on the outermost rim as a result of rebounding grit. As soon as the wear penetrates or exceeds the case hardened depth of the wheel or disc, wear is rapid because of the soft core steel underlying the case hardening. Moreover, the wear pattern on the wheels is usually uneven. As a result of the uneven wear, the rotating wheel becomes unbalanced causing severe vibration to the machine. The only remedy is to replace the wheel. The high cost and downtime incurred in replacing the wheel assembly are apparent. Because of the high cost of each wheel assembly and the machine downtime incurred in replacing such a wheel assembly, even a relatively small percent increase in wearability and thus machine operation will quickly offset the added expense of a new wheel assembly.